Waste of time. You are not allowed to link back directly to your site except for from your "About Me" page. Typically a competitor will report your listing infringement (the linkbac) and your account is suspended.

I put a few things for sale on ebay and have a link back to our site from the "about me" ebay page. I got a few hits on my auctions and zero referrals from the about me page. Our business is very small. It might be worth it if you have a lot of very popular auctions. Just a small data point.

I have seen a few cases where people can make more money selling their products on Ebay as opposed to their regular site. A friend of mine has some custom t-shirt designs he sells for about $12 on his site and he avereages over $16 each selling them on Ebay.

As far as straight traffic generation I am not sure how much you would get. If you look at the counters for items related to what you sell you can get an idea of how many people actually view the auctions. The CTR to your personal page and then on to your site would be a very, very small portion of that.

If you do link from an ebay auction to a "more info" you have to meet a few other ebay requirements, such as there being a good reason why that info couldn't be included in the auction, and that there be no links on that page to somewhere the customer would buy the product.